Review Team (February 2016).pdf

Abstract

This study validated a method to determine folic acid (FA) and 5Ͳmethyltetrahydrofolate (5Ͳ

MTHF) in the reconstituted adult nutritional/infant milk formula, according to the AOAC

single laboratory validation guidelines. Heat treatment in a boiling water bath was

performed to extract folate, followed by solid phase extraction and treatment using the

Amicon membrane filters prior to analysis using ultra performance liquid chromatographyͲ

tandem mass spectrometry (UPLCͲMS/MS). The limit of detection (LOD) for FA was 0.14

μg/100 g determined using the laboratory made rice milk as a blank matrix. The LOD for 5Ͳ

MTHF was 0.75 μg/100 g acquired from the commercial rice milk preͲtreated with

hydrochloric acid and heat. The standard calibration curve for FA was linear ranging

between 0.31 – 140 μg/ 100 g (R

=0.9998), linearity was also achieved for 5ͲMTHF over the

range of 1.6 Ͳ 140 μg/ 100 g (R

= 0.9989). The absolute recoveries were 85 % and 95 % for

FA and 5ͲMTHF, respectively. The repeatability expressed as relative standard deviation

(RSD) for both FA and 5ͲMTHF was 8 %, while RSD of the interͲday variability was 6 %. Mean

FA in SRM 1849a was 2.1 ± 0.18 μg/g fresh weight and mean 5ͲMTHF in BCR 485

(Lyophilised mixed vegetables) was 1.73 ± 0.040 μg/g (± corresponds to standard deviation).

These analysed values were consistent with the certified values indicating the accuracy of

the method. SPIFAN matrices were determined according to single laboratory validation

protocols.

Fol-20 (February 2016)

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